Edwin t



(No Model.)

B. T. GREENFIELD. FLEXIBLE ARMORED GONDUIT.

Patented Nov. 16, 1897.

PATENT FFTCEO EDWIN T. GREENFIELD, OF NEW YORK, N. Y.

FLEXIBLE ARM-ORED CONDUlT.

SPECIFICATION forming part of Letters Patent No. 593,842, dated November 16, 1897.

Application filed October 4, 1897;

To all whom it mdy concern.-

Beit known that I, EDWIN T. GREENFIELD, a citizen of the United States, residing at New York, in the county of New York and State of New York, have made a new and useful Invention in Flexible Armored Conduits, of which the following is a specification.

My invention is directed particularly to an improvement upon a flexible armored conduit described and claimed in a prior application filed by me in the United States Patent Office on the 27th day of July, 1897, and bearing Serial No. 646,099; and its object is to construct a flexible armored conduit of the type indicated in which the armor shall be securely locked together, so that the conduit may be severed at any point and the armor remain in locked position throughout its length and at the points where it is severed, and also so that it will be given increased flexibility and withstand greater longitudinal strains than was possible with the structure disclosed in my prior application above referred to.

My invention will be fully understood by referring to the accompanying drawings, in which Figure 1 illustrates in side elevational View a short length of my improved flexible conduit, illustrating also the manner of constructing the same, and Fig. 2 is alongitudinal sectional View of Fig. 1, Fig. 3 being an enlarged and elevational View of the structure as seen looking at Fig. 1 from left to right.

Referring now to the drawings in detail, T represents a flexible lining, preferably composed of vulcanized rubber.

N and M represent spirally-wound strips of metal, preferably of Bessemer steel, although they may be of any metal having the desired strength and flexibility. The inner strip M is so constructed that when wound upon the lining-tube T it presents an outward concave or curvilinear surface throughout its length and is also constructed with a central line or row of projections or lugs I I, while the outer strip N, which is wound upon it in such manner as to break joints, is curved in a reversed direction or inwardly, and has constructed upon its inner surface a series of lateral indentations D, somewhat similar in- Serial No. 654,070. (No model.)

dentations being shown between the lugs or projections I in the strip M.

S represents a strip of soft rubber or of elastic tape provided with an adhesive agent on either or both surfaces, said elastic strip being wound between the successive convolutions or spirals of the strip M, and the strip N wound thereon in the manner shown, so as to cause the central portion of the elastic or rubber strip S to adhere to the outer surface of the lining-tube T. After the tube is thus constructed it is subjected to any of the usual processes of vulcanization to the desired degree, thereby causing the rubber strip S and rubber tube T to firmly adhere to each other and to the successive convolutions of the spiral strips N and M, thus making an absolutely water-tight and perfect insulating flexible conduit.

It will be noticed that by virtue of the opposite curvature of the strips N and M and the intervening row of projections or lugs I there is formed a continuous locking-joint between all parts of the conduit or tube, such lockingjoint preventing the unwinding of the end portions of the tube and also any possibility of separating the several convolutions by longitudinal strain upon the conduit or tube. It will also be apparent that by virtue of the reverse curvature of the two strips N and M, when in position, there is given greater flexibility to the entire conduit or tube than was possible with the novel flexible armored conduit-tube disclosed in my prior application above referred to.

It will of course be understood that the projections or lugs I might be replaced by a continuous ridge or rib, but I find that better results are obtained by the use of such lugs. It is also apparent that there might be a similar series of lugs or projections extending inwardly in the strip N and adapted to depress the elastic strip S and hold it firmly against the inner tube T and also give additional longitudinal strength and locking security to the structure, and my claims hereinafter include not only this feature but all such features as would naturally suggest themselves to any one skilled in the art in the structure of such tubes. It is also obvious that there might be more than two layers of spirallywound armor-strips N and M and intervening insulating binding-strips S; but I find that a tube constructed as hereinbefore described gives ample protection both as to insulating qualities and strength or durability and is much more flexible than would be possible with more than two spiral armor-strips.

I do not limit myself, in the construction of metallic-armored conduits of the type indieated, to an armor of two metallic strips of the curvilinear structure shown, but wish it understood that my claims hereinafter made are designed to be of such scope as to include two metallic strips oppositely curved or bent in such manner that their adjoining edges will interlock in combination with a flexible lining.

Having thus described my invention, what I claim, and desire to secure by Letters Patent of the United States, is

1. A flexible armored conduit-tube consisting of a flexible lining and two or more metallic armor-strips spirally wound thereon and curved in opposite directions, substantially as described.

2. A flexible armored conduit-tube consisting of a flexible lining and two or more metallic armor-strips spirally wound thereon, said armor-strips being curved in opposite directions and breaking joints with each other, substantially as described.

3. A flexible armored cond nit-tube consisting of a flexible lining and two or more metallic armor-strips spirally wound thereon, said armor-strips being curred in opposite directions and breaking joints with each other, in combination with a strip of flexible material located between the spirals thereof, substantially as described.

4-. A flexible armored conduit-tube consisting of a flexible lining and two or more me tallic armor-strips spirally wound thereon, the armor-strips being curved in opposite directions and one of them provided with a centrally-located row of locking lugs or projections 1, substantially as described.

5. A flexible armored conduit-tube consisting of a flexible lining and two or more metallic armor-strips spirally wound thereon,

said armor-strips being curved in opposite directions and breaking joints with each other and one of them provided with a centrallylocated row of locking lugs or projections, in combination with one or more flexible strips located between the spirals of the armor, substantially as described.

6. A flexible armored conduit-tube consisting of a flexible lining of vulcanizable material and two or more metallic armor-strips spirally wound thereon, said strips being curved in opposite directions, the inner strip being provided with a centrally-located row of lugs or projections, in combination with a spirally-wound strip of vulcanizablo material located between the spirals of the armor, all of said parts being united together by vulcanization, substantially as described.

7. A flexible armored conduit-tube consisting of a flexible insulating-lining and. two or more metallic armor-strips spirally wound thereon, said armor-strips being curved in opposite directions and breaking joints with each other, in combination with a flexible spirally-wound strip of insulating material located between the spiral eonvolutions of the armor-strips, all of said parts bei ng adhesirely united together, substantially as described.

8. A flexible armored conduit-tn be consisting of a flexible insulating-lining and two or more metallic armor-strips spirally wound thereon, said armor-strips being curved in op posite directions and one of them provided withacentrally-locatedrowof loehin lugs or projections, in combination with a spirally wound strip of flexible insulating material located between the spiral convolutions of the armor, all of said parts being adhesively connected together in such manner as to be water-tight, substantially as described.

In testimony whereof I have hereunto subscribed my name this B-lth day of September, 1897.

EDXVIN T. GREENFI Elli) Witnesses:

ALLAN C. lluin\rnrm, 0. .l. KINTNER. 

